The proposed program is directed toward the determination of the feasibility and the realization of an initial design of a gyroklystron amplifier as a source for a short pulse, high frequency Electron Paramagnetic Resonance Spectrometer. It is driven by the need to make EPR measurements at higher magnetic fields. The program will include design of a driver/gyroklystron amplifier producing radiation at a single frequency between 300 GH and 360 Ghz with a peak power level of 1 kW, and a average power of 100 Watts. The pulse width will be between 10 ns and 1 ms. The capacity to produce a train of 2-3 pulses, with a fixed phase relationships, with pscing varying from approximately 50 ns to 1 ms will be included. The program is being carried out in collaboration with the National High Magnetic Field Laboratory, where a version of the EPR spectrometer will be eventually installed and used. PROPOSED COMMERCIAL APPLICATION: The gyrotron that is the focus of the SBIR is the enabling element of a high frequency, pulse EPR spectrometer. The spectrometer is expected to be of interest to a number of scientific research organizations in areas of study including the biological sciences, chemistry and physics. While the number of instruments sold would be small, the value of each instrument would exceed $500,000.